Ideally a diode turns on at zero voltage itself. Practically the diode will not turn on at zero, but it will be in the cut in voltage. When a diode is forward biased after the cut in voltage of the diode, the voltage across it remains at that value but current through it can be increased. This is the principle of clipping circuits. Consider the first positive clipper. This circuit clips the positive part of applied sine wave. During the negative half cycle, the diode will be in reverse biased condition .So the applied voltage comes across the output. During the positive half cycle, upto the cut in voltage the diode will be off. From cut in voltage diode conducts. So voltage at output remains in the same value. Clipping at any level can be obtained by properly biasing the diode with a dc power supply.

PROCEDURE

1. Setup the first circuit

2. Apply input to the circuit.

3. Observe the output in CRO and observe the transfer characteristics by pressing the X-Y key of CRO.

4. Repeat the above steps for all circuits.

5. Plot the wave forms and the transfer characteristics.

SAMPLE WAVEFORMS

1.POSITIVE CLIPPER WITH LEVEL 0.6 V

2.NEGATIVE CLIPPER AT LEVEL -0.6 V

3.POSITIVE CLIPPER WITH LEVEL 3 V

4. NEGETIVE CLIPPER WITH LEVEL -3 V

1.TWO LEVEL CLIPPER WITH LEVELS 3 V AND 5V

RESULT

Various clipping circuits were realized .Output waveforms and transfer characteristics were plotted

SAMPLE VIVA QUESTIONS

1.Mention any other name of clipper

Voltage limiter

2.Mention any of the application of clippers

In communication systems clippers were used to eliminate noise spikes.